A natural hip joint may undergo degenerative changes due to a variety of etiologies. When these degenerative changes become so far advanced and irreversible, it may ultimately become necessary to replace a natural hip joint with a prosthetic hip. When implantation of such a hip joint prosthesis becomes necessary, the head of the natural femur is first resected and a cavity is created (e.g., by reaming and/or broaching) within the intramedullary canal of the host femur for accepting the hip prosthesis, typically referred to as a femoral insert. The femoral insert may be inserted and supported within the host femur by cementing the femoral insert within the host femur. Alternatively, the femoral insert may be impacted into the host femur so that it is snugly fit and supported by the host femur.
Due to any number of reasons, however, a small portion of patients that undergo such orthopedic surgical procedures may require subsequent revision surgery to replace the hip prosthesis with a new prosthetic device generally referred to as a revision prosthesis. Because conventional hip replacement procedures typically removes a relatively significant amount of bone tissue from the area surrounding the proximal intramedullary canal, there is less bone and are significant problems associated with securing the revision prosthesis to the remaining femoral structure.
In an effort to overcome this problem, the use of short-stemmed femoral inserts is being described here. By shortening the length of the stem of the femoral insert and placing the prosthesis more proximal to standard primary femoral inserts, the need to remove surrounding bone tissue from the femoral neck and the intramedullary canal is substantially lessened. As a result, significant amounts of bone tissue are available for any subsequent revision procedures and therefore the ability to insert a traditional primary prosthesis as a revision to the short-stemmed femoral insert. This is especially beneficial for younger patients that will most likely require one or more revision prostheses during their lifetime.
Although these short-stemmed femoral inserts have aided somewhat in the preservation of femoral bone tissue, the issues of ease of insertion, prosthesis rotation, loosening, stress shielding, subsidence, and loading remain to be more fully and satisfactorily addressed.
Therefore, there remains a need for a method and apparatus for providing a short-stemmed femoral insert that is easily inserted into the femur, prevents prosthesis rotation, eliminates or lessons the probability of wear debris migration distally, eliminates or at least lessens the probability of stress shielding and subsidence, and provides surface loading as opposed to point loading.